The concept of providing materials that change color in a stretched condition is well-known. For example, U.S. Publication No. 2006/0246802 describes the use of color change laminate materials that include at least two layers of extensible materials that indicate a stretched state by exposing the previously covered coloration of a lower layer through a plurality of slit openings in the upper layer that open when the material is stretched. The color change is used to provide a means of signaling extension and/or levels of extension by a distinctive visual cue for medical applications.
Likewise, U.S. Pat. No. 7,704,589 describes an absorbent article having a built-in size indicator, wherein the size indicator is a stretchable panel that changes color when stretched.
U.S. Publication No. 2013/0251962 describes a color change compression fabric having an elastic material with one color in an unstretched condition that changes to a different color when stretched. The covering layer comprises a covering yarn that is wrapped a number of turns about an elastic yarn having a different color than the covering yarn. When the fabric is stretched, the turns of the covering yarn move apart to expose the elastic yarn underneath.
As described above, the color change occurs by allowing the lower layer to become visible through openings in the upper layer. In contrast, the use of an intermediate layer that blocks visibility of the lower layer when the material is stretched and allows the coloration of the lower layer to combine with the coloration of the top layer when the material is unstretched may provide the opposite effect. Furthermore, the prior art describes use of color changing materials to indicate when too much pressure or stretch has been applied, which is not possible should the material become permanently deformed or stretched.
As a result, it may be desirable to form an article of wear from a color changing material that is designed to block the visibility of a lower layer when stretched to achieve a color changing effect in the stretched regions of the material. It may also be desirable to form an article of wear from a color changing material to achieve an aesthetically pleasing look by permanently deforming the color changing material in areas that do not receive enough stretch during normal use to change color. It may also be desirable to form an article of wear from a color changing material to achieve an aesthetically pleasing look by permanently deforming the color changing material in areas where visual cues are not needed to indicate when the color changing material is stretched.